WASHINGTON/ADDIS ABABA, March 12 (Reuters) - The U.S. aviation regulator said on Tuesday it would not ground Boeing 737 MAX planes after a crash in Ethiopia which killed 157 people, bucking a trend of countries around the world that have suspended the aircraft's operations.

The Federal Aviation Administration's acting administrator Dan Elwell said a review by the body "shows no systemic performance issues and provides no basis to order grounding the aircraft."

The European Union's aviation safety regulator on Tuesday suspended all flights in the bloc by the 737 MAX and a U.S. Senator who chairs a panel overseeing aviation suggested the United States take similar action following Sunday's fatal crash, the second since October involving that type of plane.Of the top 10 countries by air passenger travel, all but the United States and Japan have halted flights of the 737 MAX. China, Indonesia, Singapore, Australia, Malaysia and others have temporarily suspended the 737 MAX.

U.S. Senator Ted Cruz, a Republican who chairs the Senate subcommittee on aviation and space, said on Tuesday it would be "prudent" for the United States "to temporarily ground 737 Max aircraft until the FAA confirms the safety of these aircraft and their passengers."

Cruz said he intends to convene a hearing to investigate the crashes.

Two other senators, Republican Mitt Romney and Democrat Elizabeth Warren, called on the FAA to temporarily ground the 737 MAX.

U.S. President Donald Trump also fretted over modern airplane design.

"Pilots are no longer needed, but rather computer scientists from MIT," Trump tweeted, lamenting that product developers always sought to go an unnecessary step further when "old and simpler" was superior.

"I don't know about you, but I don't want Albert Einstein to be my pilot. I want great flying professionals that are allowed to easily and quickly take control of a plane!" he added.